Automatic train conteol



Oct. 30, 1928. 1,689,738

D. c. MEARA AUTOMATIC TRAIN CONTROL Filed Jan. 11, 1926 3 Sheets-Sheet 1 gave/latex 04m) flazmsuus MEAPA 0a. so, 1928. 1,689,738 D. C. MEARA AUTOMATI C TRAIN CONTROL Filed Jan..ll, 1926 S SheetS-Sheet 2 D. c. MEARA AUTOMATIC TRAIN CONTROL l Fiied Jan. ll, 1926 5 Sheets-Sheet 5 l4 Zlwuewtoz 54 W0 Com/u 10s M54 PA atto'z wag 0.

Patented Oct. 30, 1928.

UNITED STATES v 1,689,738 PATENT OFFICE.

DAVID CORNELIUS MEARA, OF OAKLAND, CALIFORNIA, ASSIGNOR OF ONE-TENTH T ALBERT J. MOUOHOU, OF OAKLAND, CALIFORNIA.

AUTOMATIC TRAIN CONTROL.

Application filed January 11, 1926. Serial No. 80,643.

This invention relates to devices for automatically braking trains.

An object of my present invention is the provision of an efiicient and reliable automatic train control device.

Another object of my invention is the provision of a device which will permit a train carrying my device to run backwards, or against currentof traffic, without coming into contact with more than one means employed for actuating the automatic control means.

With the foregoing objects in view, together with such other objects as may subsequently appear, this invention resides in the construction and arrangement of parts hereinafter described and claimed, and illustrated in the accompanying drawings in which Figure 1 is a vertical section through a roadbed and the rails thereof, a railroad car carrying the device of my invention, and a fragment of a tripping mechanism.

Figure 2 is a section through my device shOWing cylinders and pistons therein.

Figure 3 is a section through a reduction valve employed in my device.

Figure 41 is a section taken on line 1: 1 of Figure 6.

Figure 5 a section taken on line 5-5 of Figure 1. and

Figure 6 is a bottom plan view of the device.

Referring to the drawings for more de tailed description thereof, the tripping mechanism 10 which is shownin Figure 1, may be any usual or preferred construction which may be used to actuate a lever 11 employed in my device. The tripping mechamsm 10 may be part of a block signalling system, for e2; ample, and is shown as comprising a hor1- zontal link 12 which, as shown in full lines in Figure 1, is in the path of the lever 11 so that the latter may be swung from its normal position when it comes into contact with the link 12.

Referring to Figure 6, the numeral 14 in dicates a train air line which is connected to a T 15, one end of which. is connected to a pipe line 16 and the other end of which Is connected to a pipe line 17. The pipe lines 16 and 17. arerespectively connected at 18 and 19 with a casing 20 of the device. The casing 20 comprises, as shown in Figures 1 2 and 1, a neck 21 at the upper end of which is provided a flange 22 having apertures 23 through. which may means for fastening the casing to -the underside of the car 24 shown in Figure 1. The casing 20 also comprises reduced end portions 25 and 26 providing shaft bearings and rotary valve chambers and cylinders 27 and 28 perpendicular thereto, as shown in Figure 6. At the lower portion of one end of the casing 20, there is a slot 30 through which the trip lever 11 extends outwardly from the interior of the casing, and in which it moves when actuated by link 12 of the tripping mechanism 10. The edge of the casing forming the inner boundary of the slot 30 is radially recessed the recess being lateral of the slots and is in dicated by the numeral and clearly shown in Figures 4 and 6. The lever 11 is normally retained within the recess 35 the side walls of which are beveled or rounded by a coiled spring 37 secured, as clearly shown in Figures 1 and 6, to the lever and to a member 39 which is secured to and which projects from the casing. The lever 11, the lower end of which is adapted to come into contact with the link 12 is pivotally mounted at its upper end to a collar member 42 which is inside the casing 20. The lever 11 is so pivotally mounted that it may move in and out of the recess 35 transversely of the slot 30. The lever 11 is pulled out of the recess 35 against the tension of the spring 37 when the lever comes into contact with the link 12 of the tripping mechanism.

The casing adjacent the ends of the recess 35 is slanted to facilitate the movement of the lever 11 out of the recess 35 into the slot 30. The lever 11 is pivotally mounted on a pin 11 which is secured to the collar member 42 which is mounted on a shaft 13 in a manner to turn the shaft when the member 12 1S turned by a swmgm movement of the 9 lever 11. The end portions of the shaft 43 are journaled in the casing 20 and beyond the journaled points lit into rotary valves 45 in a manner to turn the valves, there being one valve at each end of the shaft. The shaft 43 extends from the reduced portion 25 of the casing to the reduced portion 26 of the same. The above mentioned valves whichare turned by the shaft 43 are also disposed in the reduced end portions 25 and 26 and are designated by the numeral 15. These rotary valves are held in position on their seats by means of. coiled springs .47 which press on them and abut against the ends of the pipe lines 1.6 1.? respectively lever s or arm 11 is tripped by the tripping link 12,

the rotary valve which is in the reduced portion 25 of the casing isturned so that its aperture 48 allows compressed air'to pass therethrough from the pipe 16 into a pipe L9 which leads to a reduction valve-50, which is shown in detail in Figure 3. The rotary valve 45 which is disposed in the reduced portion 26 turns, of course, when the valve 45 in the reduced portion 25 turns, but does not turn to open position when the train is running in the with-traflic position.

The reduction valve 50 shown in Figure 3 isprovided with a passageway 51 which communicates at its inner end with a passageway 52. Another passageway 53 has communication with the passageway 52 and with the interior of a pipeline 54 which leads into the cylinder 27 as shown in Figure .6.

' A solid cyllndrica l member 55 is disposed in the passageway 52 and is provided with an annular peripheral groove 56 which normally communicates with passageways 57 and 58. The cylindrical block or valve 55 is normally 'held'in position closing the passageway 51 to the passageway '52, suchaction being etl'ected by a rod 60 torcedagainstthe cylindricalbloch 55 by a coiled spring (31. hen the cylindri- 0211 block or valve "55 is in the position shown in Figure 3, air may escape irom the cylinder 27 under conditions hereinafter mentioned throughthe passageway 57, the groove 56, the

passageway 58',then throughthe casingof the reduction valve and. out to the atmosphere through a passageway 63. When, however, the compressed air from the pipe line 16 enters the'reduction valve 50, it is sufficient to move the cylindrical valve 55 to the right of the position shown in Figure 8. When the valve 55 is moved to the right, the annular groove 56 is moved to the right oi the ends oi? the passageways 57 and 58 so that communication'between these passageways is cut oil', and the compressed air may flow from the passageway 51 into the passageway 52 and then into the pipe 5 2, then into the c-yl-' inder 28 where it pushes inwardly on a piston until the piston 65 moves to the right of an aperture 66 shown in Figure 2 as being in the reduced portion 28 of the casing.

The air then passes throughthe aperture66 to the atmosphere through a small tube 67 which is bent horizontally and provided for the pur- H pose of keeping dirt out of the cylinder. The

air thusescaping to the atmosphere. from the train line is reduced in pressure so that the brakes are automatlcally applied in accord anee with terns.

The piston 65 is pivoted to a piston rod 70 which is pivotally connected with the shaft 43 as shown in Figure 2. Acylinder 71 works in the reduced portion 27 of the casing and any one of numerous braking syshas a piston rod 72 pivotally connected thereto and with the shaft 43, as clearly shown in closed, The tripping at the same time opens the rotary valve and allows pressure to enter through the reduction valve into the cylinder, which pushes the piston (55 beyond the aperture 66 so as to allow the air to escape to the atmosphere through the pipe (37. The valve 55 in the reduction valve 50 is set to open forexample at eighty pounds train line pressure. \Vhen the train line pressure has been 'reduced'by the air es :aping to the atmos phere through the aperture (in and pipe (57, the valve 55is automatically closed and the lever or arm 11 is moved back by the spring 37 into its normal position. This movement of the arm 11 into normal position is elicctive in moving the piston 65 into a position closing the aperture 66, and is also effective in moving to closing position the rotary valve 45 which in the reduced portion 25 of thornsing.

When it is desired to back up the train, the lever or arm 11 is actuated in a direction opposite to that in which it is moved when running with current of traiiic. lVhen the arm 11 isso moved, it is eiij'ective to move to open position the valve 45 which is in the reduced portion 26, thevalve as in the reduced portion 25 remainingclosed. The air from the pipe line 17 then enters the reduction valve 75 shown in Figure 6. This pressure is sullicient to move a valve 7 6 which is normally kept in position by coiled spring 77. The movement of the valve 7() permits the air to pass out of the reduction valve 75 into the pipe line 78 and thence into the cylinder 28 in a manner to move the piston 71 imvardly. The inward motion of the piston 71. is ell'eetive toturu the shaft 4-3 and therefore the lever arm 11 into a substzuitially horizontal position, in which position it is retained so that the tain may be run baclm'ards or forwards against current of traliic without the lever arm coming into contact with any tripping mechanism. The tripper arm 11 may be returned to normal position when the engineer reduces the train line pressure to a certain amount, say seventy-eight pounds at which the reduction valve 75 may be set to close.

Although I have shown and described one embodiment oi my invention, it to be understood that the same is susceptible oi various changes; and I reserve the right to employ housing surrounding the shaft and slotted to allow the arm to swing transversely tor actuating the shaft, and means for yieldingly looking the arm to a side wall of the slot.

2. In a tripping device for an automatic train control, a revolvable shaft having a valve thereon, an arm pivoted relative to the shaft for swinging motion in axial direction, a housing surrounding the shaft and slotted to allow the arm to swing transversely for actuating the shaft, a recess formed in the side wall of the slot, and yielding means urging the arm into the recess, the side walls of the recess being beveled to allow the arm to climb out of the recess when struck transversely.

3. I11 an automatic train control device, a first means adapted to be moved by a tripping mechanism, a first valve adapted to be moved to open position when said first means is moved in one direction, pistons operable by said first means and adapted to operate said first means, a line having compressed air therein, a reduction valve allowing compressed air passing through said first valve to open the reduction valve and to move one of said pistons, a cylinder for said piston having an aperture for the escape of air after said piston has been moved by the compressed air, a second cylinder, a second piston in said second cylinder, a second valve adapted to be moved to open position when said first means is moved in another direction, said second valve when open being adapted to allow air from said line to pass therethrough, a second reduction valve adapted to be opened by compressed air passing through said second valve, said second reduction valve when open allowing the compressed air to move said second piston.

I. In an automatic train control device, a conduit for compressed air, a cylinder communicating therewith having a piston reciprocable therein, a rotary valve in said conduit,

means for opening the same allowing compressed air to bear on the piston, an operative connection between the piston and the valve causing the pressure 011 the piston to maintain the valve open, and a reduction valve interposed between the rotary valve and the cylinder to govern the amount of pressure entering the cylinder.

5. In an automatic train control device, a conduit for compressed air, a cylinder communicating therewith having a piston reciprocable therein, a rotary valve in said conduit, means for opening the same allowing comp'ressed air to bear on the piston, an operative connection between the piston and the valve causing the pressure 011 the piston to maintain the valve open and a reduction valve interposed between the rotary valve and the cylinder to govern the amount of pressure entering the cylinder, the latter being formed with a port leading to the atmosphere and disposed to be normally closed by the piston and to be opened when the piston is acted on by the compressed air.

6. In an automatic train control device, a conduit divided into two branches, two aXi ally alined cylinders communicating with the branches, each having a piston reeiprocable therein, a. rotary valve in each conduit, means for opening either valve allowingcompressed air to bear on its respective piston, an operative connection between each piston and its valve causing the pressure on the piston to maintain the valve open and a reduction valve interposed between each rotary valve and its cylinder to govern the amount of pressure entering the cylinder, one only of the cylinder-s being formed with a port leading to the atmosphere and disposed to be normally closed by the piston and to be opened when the piston is acted on by the compressed air.

DAVID CORNELIUS MEARA. 

